First, as an entrepreneur. Arianna co-founded the Huffington Post in 2005 and built it into a profitable $30 million business over six years. In the process, she helped create 200+ jobs, raise $35+ million of capital, and build a nationally recognized brand. She also invented a whole new kind of media business, one built from the ground up to take advantage of the digital medium, one that cleaned the clocks of dozens of richer, more powerful, and better-branded competitors. Along the way, Arianna also fought off a steady fusillade of griping and naysaying from those who dismissed her ideas as trash, theft, and idiocy, eventually overcoming these criticisms and building Huffington Post into an establishment brand.

Second, as a media mogul. With the sale of Huffington Post, Arianna becomes one of the first digital-media entrepreneurs to cash in on a scale that will even raise eyebrows in the mainstream-media-mogul community. $300 million in cash is not the sale of a "blog" for what amounts to couch change for a big media company. It's the sale of a major media business--in an industry in which most pundits have confidently asserted that it's impossible to make money. As is also traditional in the media-mogul world, the benefits of this success also accrued to Arianna personally: One analyst estimates that she made $100 million on the sale. (Matt Drudge's sources put the number at only $18 million).

Third, as a super-successful woman in what is still often a boy's club. As many have observed over the past year, tech startups and media companies still tend to be dominated by men. Success stories like Martha Stewart, Oprah Winfrey, and others are inspiring, but they're also still few and far between. With the sale of Huffington Post, Arianna now deserves to be a role model not just for entrepreneurs and media-moguls in general, but for women.

Fourth, as an American. Arianna was born in Greece, as Arianna Stassinopoulos. She moved here in the 1980s, built a national name for herself, inspired and influenced millions of people, and, eventually, amassed a personal fortune. Her life, in other words, has become a shining example of the American dream.